“You know that feeling,” the British actress and writer Phoebe Waller-Bridge asks in the opening moments of her new comedy series, Fleabag, “when a guy you like sends you a text at 2 o’clock on a Tuesday night asking if he can come and find you, and you’ve accidentally made it out like you’ve just got in yourself, so you have to get out of bed, drink half a bottle of wine, get in the shower, shave everything, dig out some Agent Provocateur business, suspender belt, the whole bit, and wait by the door until the buzzer goes?”

Waller-Bridge stands in the vestibule of her character’s London flat, her hair coiffed, her eyeliner artfully smudged, her trench coat still belted. She’s facing the camera, addressing her viewer conspiratorially. You know that feeling? Well, maybe not that exact one, but something on that spectrum? You know you do. Then the buzzer rings and her attention snaps back to the drama waiting to unfold outside her head.

Fleabag began streaming on Amazon Prime last Friday, and if you haven’t yet watched its six episodes, you should absolutely make a priority of doing so. Based on Waller-Bridge’s one-woman show, which premiered at the Edinburgh Festival Fringe in 2013 (and which was itself based on a 10-minute stand-up routine she developed for a storytelling night), the show is both extremely funny and terribly dark, a stealth one-two punch: disarming humor laying the groundwork for unnerving psychological heft.

The title refers to Waller-Bridge’s never-named antiheroine, a wayward twenty-something in London whose life, defined more by absence than substance, is quickly going off the rails. We slowly begin to understand why: Her best friend and business partner, Boo (Jenny Rainsford), recently died, leaving behind a sea of unresolved feelings and painful memories. Fleabag’s mother is also gone, and that loss haunts her daughter’s relationships with extant family members: a wary, stiff sister, Claire (Sian Clifford); an evasive, emotionally unavailable father (Bill Paterson); an undermining godmother turned stepmother (Olivia Colman). Fleabag’s longtime, on again, off again romance with the patently unsuitable Harry (Hugh Skinner) is clearly doomed; he’s sensitive and soppy; she’s unsentimental, detached, and sexually voracious. And her business, a cozy, shabby café that’s become a shrine to Boo’s love of guinea pigs, is rapidly going under.

Against this backdrop, Fleabag scrappily, cheerfully goes about her business, like a cockroach that can’t quite be killed, like an alley cat with nine lives, like a woman in denial. Critics have compared her to Bridget Jones and to Girls’s Hannah Horvath, and she shares something of the former’s charming, rumpled haplessness, something of the latter’s childish stubbornness and unrepentant, unbridled sexuality.

But those comparisons are imperfect: Fleabag is deeper than Bridget Jones, and deeply likeable in a way that Hannah Horvath isn’t. We watch repeatedly as she assesses a situation, figures out exactly the wrong thing to do, then does just that, with a big wink at the camera in the process. It’s that breakdown of the fourth wall, that sly direct address, that gets us so on board. She’s got an impish, mischievous relatability reminiscent of beloved children’s book characters; she’s a grown-up lady version of Calvin and Hobbes’s Calvin; of Maurice Sendak’s wild thing, Max; of Beverly Cleary’s Ramona.

That’s how Waller-Bridge hooks us: with a cartoon character who only slowly comes into focus as a woman more real than most we see on TV. Fleabag’s bad behavior, her various compulsions—for sex, for stealing, for pushing the buttons of the people around her—are designed to distract from more painful realities: an alarming emotional rawness, a profound sense of grief, that only emerges in the series’s second half.

Waller-Bridge, when we speak by phone, describes Fleabag as a “love story between women,” a romance about sisterhood and best friendship. She also tells me that she didn’t worry about how her British show would translate to an American audience. “This character is mainly about front, her control-freakery about how she’s perceived. I think that’s something that Brits and Americans share alike, that sense, I’m fine, I’m fine, I’m in control of everything.”

“Funny,” she adds, “is funny. And sad is sad.”

I just finished watching the series and I was struck by a moment in the last episode when Fleabag says: “Either everyone feels this a little bit, and they’re just not talking about it, or I’m really fucking alone, which isn’t fucking funny.” It struck me as a sort of summary of the whole show. Is that the question you were toying with from the beginning?It was actually literally the last thing I wrote when writing the play version. I knew I needed a line that kind of pulled everything together. I was working with Vicky Jones, who was directing the show. I was on the train up to Edinburgh, the day before the opening night. And I was like, I just don’t feel like I’ve got the idea that completely sums up the crisis of the show. Vicky kept saying, what do you want the last line to be? I was like, I want it to say something like this! And Vicky said, well fucking put it in the script, then.

I think it was in my subconscious the whole way through: Her loneliness, her fear of being able to admit that she’s lonely--that’s the thing I was most interested in writing about.

This project began as a stand-up routine, it became a one-woman show, then a pilot, then a series. Was there a point where you were like: I like this as it is. I don’t want it to evolve?No, I loved that this character just kept growing. The demand for her was really kind of extraordinary and bizarre. Even at that storytelling night, I was surprised by how many people connected to her. The aim was that it was going to be a funny and a bit sad. But the character herself, warts and all, I was really surprised that people cared. The more people connected to her, the more I wanted to do it as much as I could.

I never really wanted to let it go. I really enjoyed playing her as well. A little bit of me feels dangerous when I’m playing her, because she’s a bit dangerous.

I was scared changing it from the play. When people like something, you’re like, don’t touch it, it’s really precious, don’t break it. I found it really hard turning this into a pilot. I did have moments where I was like: It’s meant to be a play, it can’t be anything else. Then I had to shut up and just do it.

Will there be a second season?In principle, yes. But because it was a complete adaptation of the play, I feel like her story’s completed. I really desperately want to find the next story for her. I have to force myself to remember that if this were a real person, the next day would happen. So I’m taking some time to think about that.

The last episode had me basically crying at my computer.Oh no! [laughs]

We really don’t see that sadness coming. Were you consciously roping people in with humor, only to deliver an emotional blow? I guess I’m asking: Did you start with humor or with grief?Definitely with humor. And even that first 10 minutes that I wrote, I knew it was something that had to be funny. That was just the promise of the evening.

I think if you’ve got people on your side, if you’ve got people really laughing, you are able to make them cry. And the temptation [to do that] is too great. I’m a massive control freak. I want all the emotions exactly when I demand them.

When I was writing the play, and I was just kind of freewheeling, just seeing what was going to pop out, I wrote that Boo died, the speech that comes at the end of the pilot episode. I wrote that and I was like, oh shit, what have I done! There were little moments when I was surprising myself at how dark I wanted it to go. Then I got really excited. If you hear somebody say something absolutely horrendous about their own life, in quite a flippant offbeat kind of way; when you meet people clearly trying to be strong and brave, the ones who are really good at it are the ones who break my heart the most. I knew that I wanted to play with that idea.

The darkness of the second half of the show really complicates our initial reading of this character as brazenly sexual and sexually liberated. In the end we begin to see that her sexuality in part stems from a less joyous place. Do you think that changes our ability to think of her as sex-positive?No, because she still does own and enjoy her sexual appetite, and is open about it. That’s nothing she ever apologizes for or is embarrassed about. But she’s controlled by an aspect of it that she can’t help. Where she can find sex, and control, that’s where she’ll end up. Sex is what she knows. So it can turn on her, because it’s such an easy escape from the rest of her world. Her safe place becomes her dangerous place.

It’s totally liberating and important: She can own her own sex life. But I think there’s something going on in her that twists that positive thing into something negative.

That sense of her showing off, about her confidence about sex, the fact that she enjoys talking about the details of it—that’s what you kind of expect from a really modern female character. There’s a real appetite for that sexual candor. Yeah, I own it. I love it. I have it whenever I want. I can’t get enough of it.

It’s not the feeling of sex she’s going for; it’s the drama, the performance. It’s the stuff around the sex that she loves and loves talking about, loves being the person who can talk about it. I think that behavior probably belies something a little bit more complicated.

The project and the character are now a few years old. You’re no longer in your twenties. Do you feel at all alienated from this person that you made?Yeah, I suppose I’ve definitely gone to a different stage in my life. I think having that space between the play and the adaptation was actually really good. Because the material had changed a bit from the moment I sat down and started writing, when I was really feeling the most Fleabaggy. When I started adapting it for the pilot, I felt I could park all those feelings, mainly because I’d gone through the catharsis of performing it so much. And also because my life had changed. I’d gotten married and turned thirty. Thank god! I’d been waiting to turn thirty my whole life. For some reason, when I was eleven, I was like, I know thirty’s going to be good. Get through those twenties!

When I got through that, I could take a bit of distance. It became much more an experiment in rediscovering that while writing. I was focused so much on the craft of how to tell the story, letting the sadness in without the audience noticing. I think the sadness got more profound in the show than it did in the play.

But no, I still get on very well with Fleabag. I’m in a very different place now, a happy place. Not that I wasn’t in a happy place while writing it. I just feel like she’s a friend now, rather than an alter ego.